Description

Heap-based Buffer Overflow in function skip_string at cindent.c:92

vim version

git log
commit 5a8fad32ea9c075f045b37d6c7739891d458f82b (HEAD -> master, tag: v8.2.4962, origin/master, origin/HEAD)

POC

./vim -u NONE -i NONE -n -m -X -Z -e -s -S /mnt/share/max/fuzz/poc/vim/poc_h7_s.dat -c :qa!
=================================================================
==17385==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x621000013d00 at pc 0x000000566e15 bp 0x7ffe2cab62e0 sp 0x7ffe2cab62d8
READ of size 1 at 0x621000013d00 thread T0
    #0 0x566e14 in skip_string /home/fuzz/fuzz/vim/vim/src/cindent.c:92:10
    #1 0x5893c2 in find_last_paren /home/fuzz/fuzz/vim/vim/src/cindent.c:1155:12
    #2 0x58dfa6 in cin_isfuncdecl /home/fuzz/fuzz/vim/vim/src/cindent.c:1201:9
    #3 0x580d15 in get_c_indent /home/fuzz/fuzz/vim/vim/src/cindent.c:3835:6
    #4 0x9999a1 in op_reindent /home/fuzz/fuzz/vim/vim/src/indent.c:1104:16
    #5 0xbab439 in do_pending_operator /home/fuzz/fuzz/vim/vim/src/ops.c:4072:3
    #6 0xb1a7a5 in normal_cmd /home/fuzz/fuzz/vim/vim/src/normal.c:952:2
    #7 0x80ebde in exec_normal /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:8757:6
    #8 0x80e408 in exec_normal_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:8720:5
    #9 0x80dfb9 in ex_normal /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:8638:6
    #10 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #11 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #12 0xe5191c in do_source_ext /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1674:5
    #13 0xe4e376 in do_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1801:12
    #14 0xe4dcac in cmd_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1174:14
    #15 0xe4d38e in ex_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1200:2
    #16 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #17 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #18 0x7c8f31 in do_cmdline_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:586:12
    #19 0x1419502 in exe_commands /home/fuzz/fuzz/vim/vim/src/main.c:3108:2
    #20 0x141569b in vim_main2 /home/fuzz/fuzz/vim/vim/src/main.c:780:2
    #21 0x140ad95 in main /home/fuzz/fuzz/vim/vim/src/main.c:432:12
    #22 0x7fe4d382b082 in __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:308:16
    #23 0x41ea6d in _start (/home/fuzz/fuzz/vim/vim/src/vim+0x41ea6d)

0x621000013d00 is located 0 bytes to the right of 4096-byte region [0x621000012d00,0x621000013d00)
allocated by thread T0 here:
    #0 0x499ccd in malloc (/home/fuzz/fuzz/vim/vim/src/vim+0x499ccd)
    #1 0x4cb3aa in lalloc /home/fuzz/fuzz/vim/vim/src/alloc.c:246:11
    #2 0x4cb28a in alloc /home/fuzz/fuzz/vim/vim/src/alloc.c:151:12
    #3 0x1422fb5 in mf_alloc_bhdr /home/fuzz/fuzz/vim/vim/src/memfile.c:884:21
    #4 0x1421dc7 in mf_new /home/fuzz/fuzz/vim/vim/src/memfile.c:375:26
    #5 0xa5be28 in ml_new_data /home/fuzz/fuzz/vim/vim/src/memline.c:4082:15
    #6 0xa5a7d1 in ml_open /home/fuzz/fuzz/vim/vim/src/memline.c:394:15
    #7 0x4fddba in open_buffer /home/fuzz/fuzz/vim/vim/src/buffer.c:186:9
    #8 0x1416d4c in create_windows /home/fuzz/fuzz/vim/vim/src/main.c:2877:9
    #9 0x141501a in vim_main2 /home/fuzz/fuzz/vim/vim/src/main.c:711:5
    #10 0x140ad95 in main /home/fuzz/fuzz/vim/vim/src/main.c:432:12
    #11 0x7fe4d382b082 in __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/fuzz/fuzz/vim/vim/src/cindent.c:92:10 in skip_string
Shadow bytes around the buggy address:
  0x0c427fffa750: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c427fffa760: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c427fffa770: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c427fffa780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c427fffa790: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c427fffa7a0:[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fffa7b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fffa7c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fffa7d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fffa7e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fffa7f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
  Shadow gap:              cc
==17385==ABORTING

poc_h7_s.dat